This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | -72 |
| 3 | -801 |
| 4 | 5031 |
| 5 | 69912 |
| 6 | -337599 |
| 7 | -6000471 |
| 8 | 21345048 |
| 9 | 507383199 |
| 10 | -1221565689 |
| 11 | -42319604808 |
| 12 | 56627216001 |
| 13 | 3484515205449 |
| 14 | -1102289290632 |
| 15 | -283348020932001 |
| 16 | -194062588390809 |
| 17 | 22757127107101272 |
| 18 | 38476196766756801 |
| 19 | -1804851098908446231 |